December Birthday Cards - Digital Looking for December birthday cards to post on Facebook or send to someone special on email? Here are our free digital December birthday ecards themed around the main birthstone for December, Turquoise. If you are not sure how to copy the images, here are some step-by-step instructions depending on what device you are using. You have our permission to copy these images for personal use. Just a note that copyright is inherent in all creative works and you should always get permission from the owner before using any images.